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  1. 10 Oct, 2018 1 commit
    • Juergen Gross's avatar
      x86/boot: Add ACPI RSDP address to setup_header · ae7e1238
      Juergen Gross authored 
      Xen PVH guests receive the address of the RSDP table from Xen. In order
to support booting a Xen PVH guest via Grub2 using the standard x86
boot entry we need a way for Grub2 to pass the RSDP address to the
kernel.

For this purpose expand the struct setup_header to hold the physical
address of the RSDP address. Being zero means it isn't specified and
has to be located the legacy way (searching through low memory or
EBDA).

While documenting the new setup_header layout and protocol version
2.14 add the missing documentation of protocol version 2.13.

There are Grub2 versions in several distros with a downstream patch
violating the boot protocol by writing past the end of setup_header.
This requires another update of the boot protocol to enable the kernel
to distinguish between a specified RSDP address and one filled with
garbage by such a broken Grub2.

From protocol 2.14 on Grub2 will write the version it is supporting
(but never a higher value than found to be supported by the kernel)
ored with 0x8000 to the version field of setup_header. This enables
the kernel to know up to which field Grub2 has written information
to. All fields after that are supposed to be clobbered.
Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: boris.ostrovsky@oracle.com
Cc: bp@alien8.de
Cc: corbet@lwn.net
Cc: linux-doc@vger.kernel.org
Cc: xen-devel@lists.xenproject.org
Link: http://lkml.kernel.org/r/20181010061456.22238-3-jgross@suse.comSigned-off-by: Ingo Molnar's avatarIngo Molnar <mingo@kernel.org>
      ae7e1238
  3. 24 Oct, 2016 1 commit
  5. 11 May, 2015 1 commit
  7. 30 Apr, 2015 1 commit
  9. 03 Apr, 2015 1 commit
    • Borislav Petkov's avatar
      x86/mm/KASLR: Propagate KASLR status to kernel proper · 78cac48c
      Borislav Petkov authored 
      Commit:

  e2b32e67 ("x86, kaslr: randomize module base load address")

made module base address randomization unconditional and didn't regard
disabled KKASLR due to CONFIG_HIBERNATION and command line option
"nokaslr". For more info see (now reverted) commit:

  f47233c2 ("x86/mm/ASLR: Propagate base load address calculation")

In order to propagate KASLR status to kernel proper, we need a single bit
in boot_params.hdr.loadflags and we've chosen bit 1 thus leaving the
top-down allocated bits for bits supposed to be used by the bootloader.

Originally-From: Jiri Kosina <jkosina@suse.cz>
Suggested-by: default avatarH. Peter Anvin <hpa@zytor.com>
Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Ingo Molnar's avatarIngo Molnar <mingo@kernel.org>
      78cac48c
  11. 13 Mar, 2014 1 commit
  13. 29 Dec, 2013 1 commit
  15. 25 Jul, 2013 1 commit
  17. 09 Jul, 2013 1 commit
  19. 08 Feb, 2013 2 commits
  21. 01 Feb, 2013 1 commit
  23. 30 Jan, 2013 1 commit
  25. 27 Jan, 2013 1 commit
  27. 13 Dec, 2012 2 commits
  29. 26 Oct, 2012 1 commit
  31. 23 Jul, 2012 1 commit
  33. 20 Jul, 2012 1 commit
    • Matt Fleming's avatar
      x86, efi: Handover Protocol · 9ca8f72a
      Matt Fleming authored 
      As things currently stand, traditional EFI boot loaders and the EFI
boot stub are carrying essentially the same initialisation code
required to setup an EFI machine for booting a kernel. There's really
no need to have this code in two places and the hope is that, with
this new protocol, initialisation and booting of the kernel can be
left solely to the kernel's EFI boot stub. The responsibilities of the
boot loader then become,

   o Loading the kernel image from boot media

File system code still needs to be carried by boot loaders for the
scenario where the kernel and initrd files reside on a file system
that the EFI firmware doesn't natively understand, such as ext4, etc.

   o Providing a user interface

Boot loaders still need to display any menus/interfaces, for example
to allow the user to select from a list of kernels.

Bump the boot protocol number because we added the 'handover_offset'
field to indicate the location of the handover protocol entry point.

Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Peter Jones <pjones@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: default avatarMatt Fleming <matt.fleming@intel.com>
Acked-and-Tested-by: default avatarMatthew Garrett <mjg@redhat.com>
Link: http://lkml.kernel.org/r/1342689828-16815-1-git-send-email-matt@console-pimps.orgSigned-off-by: default avatarH. Peter Anvin <hpa@zytor.com>
      9ca8f72a
  35. 13 Jul, 2011 1 commit
  37. 13 Jan, 2011 1 commit
    • Lasse Collin's avatar
      x86: support XZ-compressed kernel · 30314804
      Lasse Collin authored 
      This integrates the XZ decompression code to the x86 pre-boot code.

mkpiggy.c is updated to reserve about 32 KiB more buffer safety margin for
kernel decompression.  It is done unconditionally for all decompressors to
keep the code simpler.

The XZ decompressor needs around 30 KiB of heap, so the heap size is
increased to 32 KiB on both x86-32 and x86-64.

Documentation/x86/boot.txt is updated to list the XZ magic number.

With the x86 BCJ filter in XZ, XZ-compressed x86 kernel tends to be a few
percent smaller than the equivalent LZMA-compressed kernel.
Signed-off-by: default avatarLasse Collin <lasse.collin@tukaani.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Alain Knaff <alain@knaff.lu>
Cc: Albin Tonnerre <albin.tonnerre@free-electrons.com>
Cc: Phillip Lougher <phillip@lougher.demon.co.uk>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      30314804
  39. 11 Nov, 2010 1 commit
  41. 31 Aug, 2009 1 commit
  43. 12 May, 2009 2 commits
    • H. Peter Anvin's avatar
      x86: add extension fields for bootloader type and version · 5031296c
      H. Peter Anvin authored 
      A long ago, in days of yore, it all began with a god named Thor.
There were vikings and boats and some plans for a Linux kernel
header.  Unfortunately, a single 8-bit field was used for bootloader
type and version.  This has generally worked without *too* much pain,
but we're getting close to flat running out of ID fields.

Add extension fields for both type and version.  The type will be
extended if it the old field is 0xE; the version is a simple MSB
extension.

Keep /proc/sys/kernel/bootloader_type containing
(type << 4) + (ver & 0xf) for backwards compatiblity, but also add
/proc/sys/kernel/bootloader_version which contains the full version
number.

[ Impact: new feature to support more bootloaders ]
Signed-off-by: default avatarH. Peter Anvin <hpa@zytor.com>
      5031296c
    • H. Peter Anvin's avatar
      x86: document new bzImage fields · d297366b
      H. Peter Anvin authored 
      Document the new bzImage fields for kernel memory placement.

[ Impact: adds documentation ]
Signed-off-by: default avatarH. Peter Anvin <hpa@zytor.com>
      d297366b
  45. 15 Jan, 2009 2 commits
  47. 04 Jan, 2009 1 commit
  49. 16 Dec, 2008 1 commit
  51. 11 Nov, 2008 1 commit
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  55. 31 May, 2008 2 commits
  57. 29 Apr, 2008 1 commit
  59. 26 Apr, 2008 1 commit
  61. 17 Apr, 2008 3 commits
  63. 29 Oct, 2007 1 commit